Dissociated Pattern of Activity in Visual Cortices and Their Projections During Human Rapid Eye Movement Sleep

Abstract

Positron emission tomography was used to measure cerebral activity and to evaluate regional interrelationships within visual cortices and their projections during rapid eye movement (REM) sleep in human subjects. REM sleep was associated with selective activation of extrastriate visual cortices, particularly within the ventral processing stream, and an unexpected attenuation of activity in the primary visual cortex; increases in regional cerebral blood flow in extrastriate areas were significantly correlated with decreases in the striate cortex. Extrastriate activity was also associated with concomitant activation of limbic and paralimbic regions, but with a marked reduction of activity in frontal association areas including lateral orbital and dorsolateral prefrontal cortices. This pattern suggests a model for brain mechanisms subserving REM sleep where visual association cortices and their paralimbic projections may operate as a closed system dissociated from the regions at either end of the visual hierarchy that mediate interactions with the external world.

What subjective experiences determine the perception of falling asleep during sleep onset period?

“…Generally speaking though, light sleep was associated with decreased activity in the frontal and parietal areas of the cortex and in the thalamus. Deep sleep is characterized by a further decrease in activity in these areas, as well as within the basal ganglia (e.g., Balkin et al, 2002;Braun et al, 1997Braun et al, , 1998Finelli, Baumann, Borbély, & Achermann, 2000;Kjaer, Nowak, & Lou, 2002;Maquet, 2000;Nofzinger, Mintun, Wiseman, Kupfer, & Moore, 1997;Nofzinger et al, 2002;Peigneux et al, 2001). As for stage 1 sleep, Czisch and his colleagues reported fMRI indications of reduced activation in both the auditory and visual cortex in response to auditory stimuli, as demonstrated by a decrease in the blood-oxygenation (Czisch et al, 2002).…”

Cognitive and emotional processes during dreaming: A neuroimaging view

“…Braun and colleagues (1998) found that, during REM sleep, activation within the temporo-occipital regions showed some functional dissociation: extrastriate cortex (visual association areas) activation significantly correlated with striate cortex (primary visual cortex) deactivation during REM sleep, whereas activity in both regions are usually found to positively correlate during wakefulness (Braun et al, 1997). For these authors, opposite interactions between low-and high-level visual areas during REM sleep might indicate that internal visual information is processed within a closed system (extrastriate areas and paralimbic projections, among others) dissociated from interactions with the environment (via striate cortex and prefrontal cortex, both deactivated during REM sleep; Braun et al, 1998). These early PET results are also consistent with the observation that patients with cortical blindness (after primary visual cortex or perichiasmatic lesions) report that they still dream with visual images (Solms, 1997a).…”

Learned material content and acquisition level modulate cerebral reactivation during posttraining rapid-eye-movements sleep

“…Preliminary analyses conducted on primary contrasts irrespective of prior experience revealed common rCBF increase during REM sleep (versus wakefulness) in Random, Probabilistic and Control groups in a set of brain areas previously reported to be involved in REM sleep generation (Maquet et al, 1996;Braun et al, 1998) [-2 -36 -18 mm]. Peak coordinates in these areas are less than 12 mm from previously published brain areas that activated more during REM sleep in the Probabilistic than in the Control group and also during SRT practice in the Wake group (see Table 6 in Maquet et al, 2000).…”